Chromium alloy steel and welding rod



Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE amass OHROMIUM ALLOY STEEL AND WELDING ROD Frederick M. Becket,

New York, and Russell No Drawing. Application July 28, 1934, Serial No. 737,385

4 Claims.

The invention is an alloy and a welding rod made therefrom.

Patent 1,954,344, issued April 10, 1934, to Frederick M. Becket and Russell Franks, contains a 5 description of chromium steel containing additions of columbium acting to increase the duotility and softness of the steel.

We have found that steels containing columbium tend to lose excessive amounts of this con- 1 stituent when they are melted by an oxyacetylene torch or an electric arc during welding operations unless an eifective amount of silicon is present. The following table A of test data illustrates this fact. The welds of these tests were made in twelve-gage sheet, using one-eighth inch welding rods and the electric arc method. A suitable flux, containing no uncombined metal. was employed.

Table A Analysis 0! welding rod Percent Cb Recovery in deposited oi Cb Pn'cent Percent Percent Percent metal (percent) Cr C Cb 8i 6. 32 0. 04 0. 70 0. N 0. 2o 29 6. 63 0. M 0. 76 0. 43 0. 25 33 6. 31 0. 07 1. 50 0. 80 0. W 66 6. 3d 0. C7 1. 49 1. 12 1. 23 82 6. 2) 0. M 2. 11 2. 09 1. 98 94 We have also found that siliconin substantial amounts tends to improve the ductility and softness of the chromium-columbium steels. This eflect of silicon is illustrated by the data in table B, wherein Brinell hardness numbers are given for certain steel compositions, the steel in each instance being in the as-rolled condition.

The present invention based on above described discoveries and is an alloy steel, and

a welding rod made therefrom, comprising about 2% to 30% chromium, about 0.01% to 0.5% carbon. about 0.1% to 5% columbium, about 1% to 2.5% silicon, and the remainder principally iron. 5 Several per cent. manganese and up to about 4% tantalum may also be present. The columbium content should be at least four times, and is preferably at least eight to ten times, the carbon content. The columbium content preferably ex- 10 ceeds the tantalum content. 1 Especially valuable compositions include those having a chromium content between about 4% and about 10%, those which have a carbon content not greater than about 0. 3%, and those which containless than about 3% columbium.

The welding rod of the invention preferably contains no more than about 2% silicon when the oxyacetylene process is used and no more than about 1% silicon when. the electric arc process is used.

We claim:

1. An alloy steel having substantially the composition: 2% to 30% chromium; 0.01% to 0.3% carbon; 0.1% to 3% columbium, the columbium content being at least about eight times the carbon content; more than 1% but not exceeding 2.5% silicon; the remainder substantially all iron.

2. An alloy steel having substantially the composition: 4% to 10% chromium; 0.01% to 0.3% carbon; 0.1% to 3% columbium, the columbium content being at least about ten times the carbon content; more than 1% but not exceeding 2.5% silicon; the remainder substantially all iron.

3. A welding rod having substantially the composition: 2% to 30% chromium; 0.01% to 0.3% carbon; 0.1% to-3%' columbium, the columbium content being at least about eight times the carbon content; more than 1% but not exceeding 2.5% silicon; the remainder substantially all iron.

4. A welding rod having substantially the composition: 4% to 10% chromium; 0.01% to 0.3% carbon; 0.1% to 3%co1umbium, the columbium content being at least about ten times the carbon content; more than 1% but not exceeding 2.5% silicon; the remainder substantially all iron.

FREDERICK M. BECKET. RUSSELL FRANKS. 

